[skarap]

It's hard to be sure why exactly shared libraries and dynamic linking appeared. Your explanation about reducing file size for smaller HDD and RAM footprint is probably one of the reasons, but I don't believe it's the only one - I don't remember many shared libraries from MSDOS days (where with 2MB of RAM and 40MB of HDD, storage was really scarce). In fact - I don't remember any libraries! To run Doom you just borrowed the floppies from a friend and it would 100% work. The same for Warcraft 1.

I believe it's more similar to Database Normalization from RDBMS world than to anything else. And the most important objective of Database Normalization is considered "Freeing the database of modification anomalies".

My own experience with shared libraries is pretty positive. I have fixed OpenSSL vulnerabilities many times by just updating the OpenSSL library and restarting all services. Compared to my own experience with docker where after waiting for a few weeks I had to change my base images (as nobody was updating them) updating just a single shared library and having the vulnerability fixed is way easier!

This, of course, is true if those who maintain the software you use do care about backwards compatibility (which tends to be true for the "boring" stuff and false for the stuff considered "cool" - looking at you nodejs library developers who break my build at least once a month).